How to Minimize Garden Pest and Disease Problems Next Year

As an organic gardener, I am always looking for ways
to minimize the chances of pests or diseases in my garden. I don’t use
fungicides or insecticides, even those that are all-natural and are approved
for use by organic farmers and gardeners. I want it all: tasty veggies and
healthy plants - but no interventions. And generally, I get that.

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How do I avoid pests and diseases? Give plants what
they need for optimal growth. Plants growing in great soil with appropriate
amounts of sun and moisture are generally healthy plants. It has been
scientifically proven that healthy plants are less attractive to pests and
diseases. Handpicking beetles and cleaning up the garden well are also important.

My organic corn rarely has corn worms.

A corn plant that is pumped up with chemical
fertilizer, for example, is more attractive to corn borers than one has been
raised organically and had its soil amended with manure.

I attended a lecture by Dr. Larry Phelan of Ohio State
University in which he presented results of trials comparing conventional corn
with organic corn. His data was convincing. Yes, chemical fertilizers can
produce big yields, but excess nitrogen from chemical fertilizers will attract
borers.

Then there is the problem of tomato hornworms. These
nasty, aggressive critters are a real problem for some gardeners, but I have
not seen one in my tomato patch in years. Why? I’m not sure, but the last time
I saw one, it was being parasitized by small wasps.

If you see what look like grains of rice on a tomato
hornworm, they are being attacked by a braconid wasp. The “rice” grains are
larvae that are slowly sucking the hornworm dry. If you see this happening,
don’t kill the hornworm. Just remove it (wearing gloves) and carry it far from
the tomatoes. The larvae will do the rest - and live to maturity to keep the cycle going.

How can you encourage parasitic wasps to live in your
garden? First, do not kill them – though they are not very noticeable. And do not use chemicals to kill other pests
such as Japanese beetles or potato bugs.

I have a small “home” for solitary wasps attached to
my barn. It is a box filled with bamboo tubes of different sizes, their ends
facing out. These tubes offer shelter for insects and places where they can lay
eggs or stay out of danger. I don’t see it used much, but I know that solitary
wasps do need such places. Nature offers the best places, I’m sure, so if I
don’t rake and manicure every inch of my property. A naturalistic setting
offers many sites for good bugs. Mother Nature, left to her own devices, tends
to have a balance of good critters and bad. I try not to second guess her too
often.

A home for soiltary wasps

But what about introduced species that are a problem
with our crops? They can easily cause damage and get out of control. One such
pest is the spotted winged drosophila (SWD), an Asian fruit fly that arrived in
2011. Instead of just eating overly ripe fruit laying on the ground (as most
native species do), this one will attack good fruit on the bush. Mushy fruit
(complete with bugs) is the result. Blueberries have been severely affected in
some places.

I recently phoned Dr. Alan Eaton, the state
entomologist for New Hampshire, to see if any progress has been made in
controlling this pest. No, he explained, they are still in the learning phase
at present. Early reports had suggested that early-ripening crops of
blueberries and strawberries were less susceptible to SWD. But he told me that
this year they were finding earlier and earlier reports of damage. And this
year they had reports of SWD on cherries for the first time.

These fruit pests are just one twelfth of an inch in
size, so netting (always a friend to organic gardeners) musts be very fine to
keep them off our crops. Most commercial growers are resorting to chemical
sprays. Me? I’m rooting for the birds and other insects to take charge.

So what can you do to reduce chances of pest and
disease problems next year? Clean up your garden well this fall. Apple scab,
for example, causes deformed, inedible fruit. The disease can be minimized by simply
raking up leaves and fruit- right now. This year I took it a step farther and
used a pole to knock off any apples left on the tree, and raked them up, too.
Many of those left on the tree were clearly rotten. I’ve read that spreading
compost under apple trees introduces beneficial microorganisms and may help
control diseases, too.

Cleaning up under apple trees in the fall reduces disease next year.

According to Dr. Eaton, destroying vines and leaves of
plants in the squash family – cucumbers, squash, pumpkins, melons etc. – is
important at this time of year. Striped cucumber beetles over-winter in plant
debris, so getting your garden clean is important. I put vine and tomato plants
on my brush pile and burn it once snow has fallen, but you can also bag it and
send it off with household trash. Composting is not usually an effective way of
ridding your garden of these pests.

Remember: well-tended plants are less susceptible to
diseases and less attractive to pests. I am always amazed at how healthy my
garden is despite – or because – I use no chemicals – and have always used
organic methods. It takes a while to develop a good supply of beneficial
insects, I suppose, but get started!

Want help in your garden? I make house calls - consultations - to help you plan and improve your gardens. Call me at 603-543-1307 or e-mail me at henry.homeyer@comcast.net

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